During surgery it is often necessary to supply a stream of oxygen containing gas for the patient's lungs. An endotracheal tube is often found to be a convenient means for supplying a gas stream for the patient's lungs. An endotracheal tube is a tube through which anesthetic gases or vapors, as well as the respiratory gases, are conveyed into and out of the trachea. A standard form of endotracheal tube is made of plastic tubing and has an end inserted into the patient's trachea. A balloon is attached to the plastic tube near the end which is inserted into the patient's trachea, and a second tube is supplied for inflating the balloon. After the endotracheal tube is inserted into the patient's trachea, the balloon is inflated in order to seal the trachea so that the endotracheal tube is the only path for gas to enter and leave the patient's lungs.
When laser surgery is performed on the interior of the patient's throat, the plastic endotracheal tube presents a problem. Laser surgery usually employs a light source (the laser, and the light may be visible, infrared, or ultraviolet) to burn away tissue which the surgeon desires to remove. Also the laser light will burn a hole in the plastic endotracheal tube. A burn in the endotracheal tube may be dangerous for the patient for several reasons, including: the patient's supply of anesthetic gases and oxygen may be interrupted; the oxygen being delivered to the patient through the endotracheal tube may promote combustion causing the plastic endotracheal tube to flare into a flame; and smoke caused by the burn of the plastic tubing both may be toxic to the patient and may obstruct the surgeon's view of the patient's throat. A pressing problem in the field of laser throat surgery is to protect the endotracheal tube from the laser beam.
A shield for protecting an endotracheal tube from laser light has been disclosed, where the shield is made by mixing powdered metal with a plastic resin and applying the metalized resin to the surface of the plastic endotracheal tube, Ferraro et al. in U.S. Pat. No. 4,489,722 issued Dec. 25, 1984. Also a laser resistant material made by putting a dispersion of graphite powder in a polymer matrix is disclosed by Laptewicz, Jr. et al. in U.S. Pat. No. 4,611,588 issued Sept. 16, 1986. Also, protection of an endotracheal tube from laser light by flushing the volume enclosed by the patient's throat by using a stream of flowing nitrogen gas along with a metal shield to protect the balloon of the endotracheal tube is disclosed by Milhaud in U.S. Pat. No. 4,378,796 issued Apr. 5, 1983.
To be useful in practical surgery, a laser resistant endotracheal tube must have at least the following properties: be sufficiently flexible to conform to the shape of a patient's throat; be protected from rupture by heat from the laser beam; and produce a minimum of smoke when struck by the laser beam. Also, specular reflection of the laser beam from a metallic surface may cause the laser beam to reflect at nearly full intensity, strike the patient's tissue at an undesirable location, and cause an unwanted burn where the tissue is struck. The methods of protecting an endotracheal tube from laser light suggested in the prior art have not provided a satisfactory laser resistant endotracheal tube. Particularly, no adequate method of shielding the balloon of the endotracheal tube from laser light has been disclosed.
A further need in laser surgery is to have flat sheet laser resistant material in order to make drapes to protect equipment during laser surgery. For example, plastic tubing carrying gases or fluids to a patient are susceptible to rupture if they are struck by the laser beam. For example, during skin surgery it is possible for operating room equipment to be damaged by a misdirected laser beam.
Further, no satisfactory laser resistant flat sheet material suitable for making surgical drapes has been disclosed in the prior art. Aluminum foil or aluminum coated sheet plastic such as mylar have been tried, but have the disadvantage that a specular reflection of the laser beam can occur from the material. The reflected beam may not have its intensity sufficiently reduced, and therefore may be of sufficient intensity to damage equipment or injure personnel.